package main

func main()  {

}

type xtnode struct {
	val int
	left *xtnode
	right *xtnode
}
func xtshu(l,r *xtnode) bool {
	if l == nil || r == nil {
		return l == nil && r ==nil
	}

	return l.val == r.val && xtshu(l.left,r.left) && xtshu(l.right,r.right)
}
